A series of investigations conducted over the last three years has shown older adults to require larger visual information processing times than the young to complete peripheral and central processes. Other investigations have revealed age differences in the processing speed and the organization of certain visual search and selective attention tasks. The objectives of this renewal proposal are: (a) to further explore the variables that might explain the large age differeces in selective attention found in our earlier investigations and (b) to investgate age differences in visual search and attentional phenomena using a search and detection paradigm reported by Schneider and Sheffrin (1977). The procedures of these investigations will include tachistoscopic presentation of visual displays and will measure subjects' accuracy of perceptual identification and reaction time. The first four experiments will examine the relationship between aging and selective attention as measured in partial report tasks. The major variables of interest will be the time course of selective attention and the number, spacing, and nature of noise elements presented in visual displays. The visual search experiments will investigate age differences in the effects of processing load on controlled search and automatic detection. We will also examine age differences in the rate of learning and relearning a set of automatic-detection responses.